Hydraulic control valve



May 30, 1950 H. J. STACEY ETAL HYDRAULIC CONTROL VALVE Filed Juli; 10, 1946 2 Sheets-Sheet l y 1950 H. J. STACEY ETAL 2,509,257

HYDRAULIC CONTROL VALVE Filed July 10, 1946 2 SheetsSheet 2 iln-ucnfom 24 /2 4 4%, 'W M. JM M M M Patented May 30, 1950 HYDRAULIC oou'mor. VALVE Hugh J.

Schmiel, Cleveland,

Stacey, wlllogghlliby, and Herbert H.

o, assignors to Bydraulic Equipment Company, Cleveland, Ohio, a corporation of Ohio Application July 10, 1946, Serial No. 682,718

7 Claims.

This invention relates to a hydraulic control valve which is operable as a pump. Control valves of this general type are used in the operation of hydraulic rams or hoists and the valve of the present invention is intendedto provide for emergency manual pump operation when there has been failure in the normal supply of high pressure fluid.

It is, therefore, a principal object of this invention to provide means for optionally converting a hydraulic control valve having a reciprocating plunger into a hand pump.

A more specific object of the invention resides in the combination with a hydraulic control valve of auxiliary check valve means which may be adjusted to condition the hydraulic system with which it is used for manual pump operation.

An additional specific object is to provide a simple and dependable form of auxiliary check valve means which may be set in operable relation to a hydraulic system including a control valve and a hydraulic motor device for the purpose of applying pressure to the hydraulic motor device, and unset to permit relief of the pressure thus applied.

These and other features of novelty contributing to emciency of operation, versatility in use and ease of manufacture will be more clearly understood from the following detailed description of a preferred embodiment of the invention taken in connection with the accompanying drawings, in which:

Fig. 1 is a side elevation of a hydraulic unit comprising a pump, a control valve and a reservoir tank;

Fig. 2 is a horizontal sectional view of the control valve taken on line 22 of Fig. 1;

Fig. 3 represents a vertical sectional view of the control valve takenon the line 3-3 of Fig. 2; and

Fig. 4 shows an enlarged vertical section of the auxiliary check valve means, taken along the line dl of Fig. 2.

With reference to Fig. 1, indicates a combination hydraulic unit comprising a power driven gear pump it, a control valve M and a reservoir tank It, all joined together in compact integral relation for efficient operation.

The tank It is provided at the top with a breather cap and filler plug l B and at the bottom with a. drain plug ill, by means of which a hydraulic fluid such as oil may be conveniently added or removed.

The illustrative control valve it includes an outwardly projecting valve plunger 22 which is of the hollow type and arranged for reciprocation by a pivotally connected operating lever 24.

A combination unit of this general type, including a hollow control valve plunger enclosing relief and check valves is disclosed in W. T. Stephens Patent No. 2,362,945, granted November 14, 1944.

Referring now to Figs. 2 and 3, it will be seen that the valve plunger 22 moves in a closely ntting plunger bore 26 extending through a chambered housing 28. Spaced pairs of vertical screws 30, 30 and 32, 32 extend through respective end passages or chambers 34 and 36 for securing the control valve M in tight sealing relation to the adjacent face of the reservoir tank I 6. These end passages 34 and 36 intersect the plunger bore 26 to provide part of the hydraulic circuit of the valve.

As will be understood, the gear pump l2 may be rotated by any suitable motor or by a power takeofi connection from a tractor or other enginedriven vehicle. The high pressure delivery end of the pump 12 is connected with an entrance port 38 extending from the bottom of the valve housing 28 to a transverse passage 40 intersecting the plunger bore 26 at a point adjacent the transverse end passage 34. A low pressure return port 42 extending downwardly from one end of the passage 36 (Fig. 2) returns hydraulic fluid to the tank It. A central transversely extending service passage M also intersects the bore 26 and. leads to a service port 46 which is diagrammatically shown as connected to a single acting hoist 48. A screw plug 50 closes an optional service port 52 at the other end of the passage M.

As will appear more fully, the operation of the control valve it as a pump requires a fluid connection between the hoist 48 and the end passage 36 that is independent of the plunger bore 26. The relatively small displacement of the reciproeating valve plunger 22 requires, as a practical matter, that check means be included in this fluid connection in order to prevent return flow from the hoist 48 after a single pumping stroke of the plunger and before the hoist 43 has been fully extended. The preferred manner of providing the fluid connection and check means as an integral part of the valve it will now be explained in detail.

The upwardly extending portions of the passages 36 and 44 shown in Fig. 8 are connected by a counter bored passage 54 seating a spring pressed, ball check valve member 56 which is operative under manual pumping conditions to prevent return flow from service passage 44 to end passage 36. A transverse extension 58 of indicated in dotted lines in Fig. 1.

the return passage 66 is also in circuit with the checked connecting passage 64 and connects directly with a tank return port 66 (Fig. 4) having a threadedly secured pipe 62 extending downwardly below the level oi oil in the tank I6, as The end passage 36 and its extension 56 will provide a pump chamber for cooperation with the valve plunger 22, acting as a piston, in the emergency emanual operation of the control valve as a pump.

The hollow valve plunger 22 is centered in the neutral position of Fig. 2 by means of a spring 64 closely coiled around its reduced diameter right end and held in place by a screw cap 66 threaded into the plunger. A shoulder 66, which is formed by the counter boring of plunger bore 26, provides a socket and fixed abutment for the inner end of spring 64. An opposed abutment is provided at the other end of spring 64 by the adjacent portion of a hollow screw threaded cap 16 closing the corresponding end of the valve bore 26.

The hollow valve plunger 22 is formed also with an extended land portion I2 closely fitting the 'bore 26 at the left end, where it passes through an annular seal device I4. An elongated grooved or reduced portion I6 extends between the land portion 12 and another land portion 18, the right end of which is engageable with the centering spring 64. The hollow plunger 22 is further provided with a central passage 66 of reduced diameter, affording a seat 62 at its left end for a spring pressed ball 64 of a reliei. valve and a similar seat 66 at its other end for a spring pressed ball 66 of a check valve. A spaced series oi. radially extending ports 96, 66 is formed in the hollow plunger 22 adjacent the relief valve ball 64 and a similar set of radially extending ports 92, 92 is formed in the land portion I6 and between the two valve balls 84 and 68. In its seated position the check valve ball 86 is encircled by a further group of radially extending ports 94, 94 which also pass through the land portion I6 of the plunger 22.

Fig. 4 shows a fragmentary section of the chambered housing 28 which has a step bored opening 96 for accommodation of a plug type check valve 96 which is employed in the manual pumping operation. The opening 96 has a threaded lower end portion 566 engaging a corresponding threaded end I62 of a hollow cylindrical cap I64. This cylindrical cap I64 is formed with an intermediate, extended, shoulder portion 36, slidable in the enlarged upper part of the bored opening 96 and grooved intermediate its length to receive a peripheral sealing ring I68. The cap I64 also includes a head H6 which is shown to be in engagement with a slotted retaining ring I it attached to the valve housing 26 by means of screws H6, H6. The washer-like retaining ring H2 cooperates with head M6 to prevent insertion of the hollow cap I 64 beyond the position of Fig. l, and also to prevent undesired withdrawal of this can by serving as a stop for the shoulder portion I66.

In normal, upright position of the control valve I4 the check valve 98 will close promptly without assistance from the compression spring II 6, but to insure its efli cient functioning in all possible operating positions the spring should be used.

The head II6 of the hollow cap W4 is threaded to receive a screw plug H6 against which reacts the upper end of a compression spring H8 arranged to hold the check valve 98 resiliently seated against return port 66. It will also be noted that the check valve 96 has an extended shoulder I26 snugly fitting within the cylindrical cap I64 and that an inwardly extending flange I22 on the lower end of this cap is engageable with shoulder I26 to prevent separation of the valve 98 from the cap.

In Fig. 1 the check valve assembly is shown in a raised position which results in a positive unseating of the check valve 96 by the flange I22. and its elevation to a position clear of the tank return port 66 and the adjacent return passage extension 66.

In normal operation the check valve 96 will not be used, but if for any reason other than a shortage of hydraulic fluid the pump I2 becomes inoperative, the hoist 46 can be extended by utilization of the plunger 22 as a hand pump, and can be subsequently retracted by proper manipulation of the cap I64 supporting the check valve 96 to clear the return port 66. The functions of the control valve and the auxiliary check valve.

will now be described in detail.

When the valve plunger 22 is in the neutral position shown by Fig. 2, pressure fluid entering the valve housing 26 from the high pressure inlet port 66 will reach chamber 46, flow freely through the valve bore 26 adjacent the plunger grooved portion I6, and thence into the end passage 64. The port 42 extending into the passage 64 will return the thus bypassed hydraulic fluid back to the tank I6.

Pulling the plunger 22 out, that is, moving it to the left of the position shown in Figs. 2 and 3 and against the action of compression spring 66, will place the intermediate plunger ports 92, 92 in communication with the passage 46 and the end ports 94, 94 in communication withthe central service passage 44. Fuid under pressure will then flow from the inlet 68 to the passage 46, through the ports 92, 92 and along the central rplunger passage 66 to unseat the check valve ball 66 and discharge pressure fluid into the service passage 44. This pressure fluid will continue its flow from the passage 44 to the hoist 46 for the ,operation of whatever device is attached thereto.

Reverse movement of the valve plunger 22 inwardly against the compression spring 66 abutting the hollow cap I6 will result in a return flow of hydraulic fluid from the hoist 48 as the plunger ports 92, 92 are placed in communication with the service passage 44, and the end ports 94, 94 are opened by the check valve ball 66 to the passage 36 which leads to the passage extension 56 and the tank return port 66.

The relief valve ball 64 will be unseated it abnormal pressure is built up during the extend operation of hoist 48, in which event the pressure will be relieved by exhaust through the plunger ports 96, 96, which are at that time open to the end passage 34 connected to the low pressure return port 42.

Assuming a power failure or breakdown of the gear pump I2 when the hoist 46 is in the position indicated in Fig. 2, it will be possible to extend it manually by turning down the head II6 to permit the spring I16 to resiliently seat the check valve 96 in the return port 66, thus preventing return flow of fluid to the tank I6. Reciprocation of the hollow valve plunger 22 will then produce a pumping action effective to extend the hoist 46. As the plunger 22 is pulled out to the left of Fig. 2 a vacuum will be created in passage 36 causing the valve 66 to be lifted from its seated position and fluid under atmospheric pressure in the tank It to enter the valve housing 28 by way of port 80. when the plunger 22 is pushed in the opposite direction the check valve 98 will move to closed position and fluid under pressure will be forced through the end passage 36, to the check valve member 68, through passage 5i and into the service passage 44, whence it will flow to the hoist 48. This reciprocating operation will be repeated until the hoist 48 has been moved to its extended position or any intermediate position which is desired.

To retract the hoist 48, it is necessary that the head Ill! be turned to unscrew the threaded end m2 of the hollow as m, which will raise the check valve 98 clear of its seat and allow return flow from the chamber 36 to the reservoir it. This return flow is then accomplished by moving the plunger 22 inwardly to its normal retracting position.

The advantages offered by the novel means which have been provided for the emergency operation of a plunger type control valve as a pump will now be fully apparent. As a practical example, it may be noted that the blade of a bulldozer left in grounded position by failure of power or gear pump may be conveniently and efllciently lifted with the pump operable valve of this invention, thus permitting towing of the vehicle on which the bulldozer blade is mounted.

As it will be obvious to those skilled in this art that the principles of the invention which have been specifically described herein may be varied in details and mode of application, it is not intended that the invention shall be limited other than as may be required by the scope of the appended claims.

Having thus described our invention, what we claim as novel and desire to secure by Letters Patent of the United States is:

1. In a hydraulic control valve, the combination comprising a valve housing provided with an inlet passage for pressure fluid, a service passage spaced at one side of the inlet passage, a

return passage spaced farther from the inlet passage on the same side, a plunger bore intersecting the said passages, a valve plunger reciprocable in said bore and formed for operable cooperation with said passages, an enclosed intercommuni cating passage extending between the return passage and the service passage and separate from the plunger bore, a check valve arranged to prevent flow in the intercommunicating passage from the service passage to the return passage, and an auxiliary check valve assembly mounted in said housing and optionally movable to a position in the return passage to prevent the return of hydraulic fluid there-- through.

2. In a hydraulic control valve. the combination comprising a valve housing provided with aninlet passage for pressure fluid, a service passage spaced at one side of the inlet passage, a tank return passage spaced farther from the inlet passage on the same side, and a plunger bore intersecting the said passages; a valve plunger reciprooable in said bore and formed for operable coperation with said passages, said valve housing being also provided with an intercommunicating passage between the service passage and the tank return passage spaced laterally from the bore, a check valve arranged to prevent flow in the intercommunicating passage from the service passage to the tank return passage; and an auxiliary check valve assembly mounted in said housing and positionable to prevent normal return flow of hydraulic fluid from the tank return passage, whereupon the control valve may be operated as a pump, said auxiliary check valve assembly being also positionable to permit unrestricted flow out of the tank return passage when the control valve is not to be operated as a pump, and said auxiliary check valve assembly including a check valve member, and a sleeve threaded into saidhousing and supporting the check valve member, whereby the check valve member may be moved from an inoperative to an operative position with respect to saidtank return passage by rotation of the sleeve from without the housing.

3. In a hydraulic control valve for use with a single acting hoist, the combination comprising a valve housing provided with a pressure fluid inlet passage, a service passage, and a tank return passage spaced in the orderrecited, a plunger bore intersecting the said passages, and an interconnecting passage between the service passage and the tank return passage laterally spaced from the plunger bore; a valve plunger reciprocable in said bore and formed for operable cooperation with the passages intersected thereby; one-way check means associated with the connecting passage and constructed and arranged to permit flow of hydraulic fluid from the tank return passage to the service passage; and an auxiliary check valve assembly mounted in saidhousing and manually positionable to prevent normal return flow of hydraulic fluid from the tank return passage, whereupon the control valve may be operated as a pump, said auxiliary check valve assembly being also optionally and manually positionable to permit unrestricted flow out of the tank return passage when the control valve is not to be operated as a pump.

4. In a hydraulic control valve for use with a single acting hoist, the combination comprising a valve housing provided with a pressure fluid inlet passage, a service passage, and a tank return passage spaced in the order recited, a plunger bore intersecting the said passages, and an interconnecting passage separate from the bore extending between the service passage and the tank return passage; a valve plunger reciprocable in said bore and formed for operable cooperation with the passages intersected thereby; one-way check valve means associated with the connecting passage and constructed and arranged to permit flow oi! hydraulic fluid from the tank return passage to the service passage; and an auxiliary check valve assembly mounted in said housing and positionable to prevent normal return'flow of hydraulic fluid from the ,tank return passage, whereupon the control valve may be operated as a pump, said auxiliary check valve assembly being also positionable to permit unrestricted return flow of hydraulic fluid from the tank return passage when the control valve is not to be operated as a pump, and said auxiliary check valve assemblyincluding a check valve member, and a sleeve threaded into said housing and supporting the check valve member, whereby the check valve member may be moved from an inoperative to an operative position with respect to said tank return passage by rotation of the sleeve from without the housing.

5. The combination with a reservoir tank constructed to expose a contained hydraulic fluid to atmospheric pressure, of a hydraulic control valve having a valve housing provided with a plunger bore, said housing having an inlet passage for high pressure fluid, a discharge passage at one side of theinlet passage, 3, service passage on the other side of said inlet passage for connection to a hoist, a return passage beyond the hoist passage, and an intercommunioating passage between the return passage and the service passage spaced laterally from the bore; a conduit connected to the return passage and adapted to extend below the level of hydraulic fluid in said tank; a check valve arranged to prevent flow in the intercommunicating passage from the service passage to the return passage; a valve plunger reciprocable in said bore and ported for cooperation with said passages, said porting being such that in the neutral position of the plunger the first two passages are in full open communication, the remaining passages positively closed, and said hoist connection passage being closed against flow in either direction; and a Pump check valve positionable in the return passage and arranged to prevent return of hydraulic fluid therethrough to the tank, whereby reciprocation of the plunger in one direction will produce a vacuum in the return passage and induce a flow of fluid from the tank past the pump check valve, and reciprocation in the other direction will force fluid from the return passage to the service passage.

6. The combination with a reservoir tank constructed to expose a contained hydraulic fluid to atmospheric pressure, of a hydraulic control valve having a valve housing provided with a plunger bore, said housing having an inlet passage for high pressure fluid. a discharge passage at one side of the inlet passage, a Service passage on the other side of said inlet passage for connection to a hoist, a return passage beyond the hoist passage, and an intercommunicating passage between the return passage and the service passage spaced laterally from the bore;

' a conduit connected to the return passage and adapted to extend below the level of hydraulic fluid in said tank; a check valve arranged to prevent flow in the intercommunicating passage from the service passage to the return passage; a. valve plunger reciprocable in said bore and ported for cooperation with said passages, said porting being such that in the neutral position of the plunger the first two passages arein full open communication, the remaining passages positively closed, and said hoist connection passage being closed against flow in either direction; and 225L274 a pump check valve assembly positionable in the return passage and arranged to prevent return of hydraulic fluid therethroug-h to the tank, whereby reciprocation of the plunger in one direction will produce a. vacuum in the return passage and induce a flow of fluid from the tank past the pump check valve assembly, and reciprocation in the other direction will force fluid from the return passage to the service passage, and said pump check valve assembly including a spring-seated check valve member, and a sleeve threaded into said housing and supporting the check valve member, whereby the check valve member may be moved to a wholly inoperative position by rotation of the sleeve.

7. A combined hydraulic control valve and pump, comprising, a valve housing provided with a pressure fluid inlet passage, a service passage spaced at one side of the inlet passage, a fluid return passage spaced farther from the inlet passage on the same side and adapted to form a pump chamber, a valve plunger bore intersecting the said passages, and an enclosed intercommunicating passage extending between the return passage and the service passage and separate from the plunger bore; a valve plunger reciprocable in said bore and ported for cooperation with said inlet, service and return passages, the porting being such that in the neutral position of the plunger the inlet passage and the service passage are closed to communication and the service passage is closed to the return passage; check valve means arranged to prevent flow in the intercommunicating passage from the service passage to the return passage; and a pump check valve adjustably mounted in the valve housing and optionally movable to a pumping position in the return passage preventing normal return of hydraulic fluid therethrough.

HUGH J. STACEY. HERBERT H. SCHMIEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,753,562 Ferris Apr. 8, 1930 1,775,613 Ferris Sept. 9, 1930 Ernst Aug. 5, 1941 

